6 BRA 12 twist testing (update 3-4-18)

[Badbob]

All I can say is wow! I wish my 6mmbr and my 6x47 put up groups like that. I just got the 80g Dominators to use in my 6BR, 1:10, shooting at 6600ft, with the hope that I can shoot that consistently. I have N135 and H4895 on hand along with BR-4, 450s, 205m, 6 1/2 and 7 1/2 primers.

Is it worth seeking out a can of IMR8208?

it sounds like you would recommend starting into the lands but at least .012" i was thinking about starting touching the lands but was not sure what these Dominator's like.

What is the action, scope, and stock you are using for this rig? Would you say the groups are more attributed to your skill as a reloader or a shooter? In other words, could a novice shooter shoot those groups with your rig?

Again, very impressive and gives me something to aspire to. Thanks for sharing. BB

 

[WyleWD]

Is it worth seeking out a bottle of 8208? --- For the 1-12 or 1-10tw, yes and pick up some 450 primers while you're at it.

And James is among the BEST when it comes to load development and is a very high level shooter. JME. WD

 

[Badbob]

I manage to find, amidst the shortages, to 1 pounders of 8208 at my local Bass Pro! Turned around and went to another shop and found 2 bottles of my pistol powder HS-6. It was a good day shopping!.

I do have 450s on hand so I'm good to go with trying this combo. Bedding my action on new stock that I'll shape to be a tracker style and I'm off to the range, hopefully, in a week.

Stay tuned. BB

 

[Gabe22BR]

Oh boy!!

 

[Badbob]

Range Report

I sure could use some help with intepreting the data. Was hoping some better groups to launch this investigation into Bart's 80g.

The gun:
26" Heavy Varmint Criterion 1:10
6600 ft elevation
IMR8208 with 205m primers
Jam=.012"
R700 trued action; Jewel Trigger Sightron 8-32x
Wind 4-5, steady on at 90 degrees from the left.
41 degrees 1020mmHg

The sighters where 31.4g, touching.

SD was single digits from 31.4 to 32.2 (basicall 3 and 4). I'm happy with that!
Best groups, in the 4s! BARF! 31.6 to 32.2 (4x sighters measured .257")
Overall look at speed is a steady incline . . . not seeing any flatting of speeds between groups to represent a node.

Question: Seems to be some odd looking holes in my target. Not quite keyholing. I do have a nice solid piece of plastic sigh (like those political signs you see on street corners).

Is this worth pursuing? should I scrape IMR 8208 and try some N125? Perhaps reload with 450s? Try touching the lands like I did with the sighters?

Any thoughts and your help is most appreciated.

 

[BartsBullets]

How fast were you shooting them and what caliber? Also did you have flags out?

Bart

 

[Badbob]

How fast were you shooting them and what caliber? Also did you have flags out?

Bart

Yes to the flags . . .6mmBR . . . as for speeds see attachment. Many thanks! BB

 

[BartsBullets]

Yes to the flags . . .6mmBR . . . as for speeds see attachment. Many thanks! BB

Your load is probably going to be around 31.6 to 31.8. Go into the rifling with the bullet. You should find something around .006 to .012 thousandths in. Your groups have a lot of horizontal so keep an eye on those wind flags.
Hope this helps!
Bart

 

[Badbob]

Your load is probably going to be around 31.6 to 31.8. Go into the rifling with the bullet. You should find something around .006 to .012 thousandths in. Your groups have a lot of horizontal so keep an eye on those wind flags.
Hope this helps!
Bart

Thanks Bart! I was in .012" . . . sounds like you are in favor of sticking with 8208 and looking for a node around 3180fps, or 31.6 to 31.8, correct? thanks BB

 

[WyleWD]

Thanks Bart! I was in .012" . . . sounds like you are in favor of sticking with 8208 and looking for a node around 3180fps, or 31.6 to 31.8, correct? thanks BB

I wouldn't scrap the 8208 out or the 205 primers until you give it a try with 450 primers. 450's Made a very pronounced difference to the best. I settled on approximately .007 into the lands, and between 31.3 and 31.8. YMMV. I also tried N135 and from what I've tried, and what I've seen out of other BR's it's worth a try, I've seen it work pretty well in 12 and 14twist 6br's. Again, YMMV as you're a few thousand feet higher than I am here. JME for what it's worth. WD

 

[JamesnTN]

I don’t want to hurt your feelings but probably two of the most hardest barrels to tune in any 6mm variant is a 9 and 10 twist. They can be but very temperamental. If all you want to shoot are 70-80 grain bullets I’d really suggest a 12 twist.
Pick a bullet and build your barrel and chambering around the bullet.

 

[JamesnTN]

Your load is probably going to be around 31.6 to 31.8. Go into the rifling with the bullet. You should find something around .006 to .012 thousandths in. Your groups have a lot of horizontal so keep an eye on those wind flags.
Hope this helps!
Bart

Bart he has a 6 BR not a BRA 31.6-31.8 is gonna be a bit too hot for the 80 grain bullets. that’s where I’m at in my BRA and your 80 grain bullet.

 

[BartsBullets]

Bart he has a 6 BR not a BRA 31.6-31.8 is gonna be a bit too hot for the 80 grain bullets. that’s where I’m at in my BRA and your 80 grain bullet.

James,

My BRA at 3550 is starting to get hot with an 80gr Dominator. If you look back at the posts I check specifically to see what caliber was being used. If you look further Bob went up to 3280 at 32.2 and got some flatting primers but normal bolt lift. My recommendation of working around 31.6 to 31.8 is within what his 6BR can handle. Granted I don’t want to see him push it much harder.

Also tuning at 3180 and below on another node is an option.

Bart

 

[Tim Singleton]

Range Report

I sure could use some help with intepreting the data. Was hoping some better groups to launch this investigation into Bart's 80g.

The gun:
26" Heavy Varmint Criterion 1:10
6600 ft elevation
IMR8208 with 205m primers
Jam=.012"
R700 trued action; Jewel Trigger Sightron 8-32x
Wind 4-5, steady on at 90 degrees from the left.
41 degrees 1020mmHg

The sighters where 31.4g, touching.

SD was single digits from 31.4 to 32.2 (basicall 3 and 4). I'm happy with that!
Best groups, in the 4s! BARF! 31.6 to 32.2 (4x sighters measured .257")
Overall look at speed is a steady incline . . . not seeing any flatting of speeds between groups to represent a node.

Question: Seems to be some odd looking holes in my target. Not quite keyholing. I do have a nice solid piece of plastic sigh (like those political signs you see on street corners).

Is this worth pursuing? should I scrape IMR 8208 and try some N125? Perhaps reload with 450s? Try touching the lands like I did with the sighters?

Any thoughts and your help is most appreciated.

You might slip another scope on !
Those two in a hole and one an inch out don’t make much sense

 

[Ccrider]

You might slip another scope on !
Those two in a hole and one an inch out don’t make much sense

Gun handling?

 

[DBLNUT]

My BRA really did not shoot the 80's well until I started to push them a little faster. 33.0 of 8208 and about 4 off the lands gives me 3385 over the Labradar. 5 shot groups.

 

[WyleWD]

Gun handling?

+1^^ Also, with a 90* wind it could be that the 31.4-31.8 window node was missed due to a pickup and or let off in the wind (post#25). WD

 

[Badbob]

I don’t want to hurt your feelings but probably two of the most hardest barrels to tune in any 6mm variant is a 9 and 10 twist. They can be but very temperamental. If all you want to shoot are 70-80 grain bullets I’d really suggest a 12 twist.
Pick a bullet and build your barrel and chambering around the bullet.

Thanks James . . . the last thing I want to be doing is chasing my tail. The 1:10 barrel was bought to shoot 67g FB Fowlers, which I still have a box of so I could go back and work on those. I'm not sold on the 80g just thought it would be a better bullet for the 1:10 here at 6600ft. This guy is setup for me to practicing my reloading, tuning and shooting skills at the bench and nothing more, other than perhaps some Pdogs or a goat.

I have a 6x47 I use for 105 class bullets. Having a smaller caliber is just for fun and learning. Thanks BB

 

[Badbob]

Gun handling?

Well, what can I say . .. this gun is for skill building at reloading and shooting bench. It felt pretty locked down in the front and rear. There was a mph cross wind. I just need to be honest and realize the gun is probably better than my skill level. Sigh . . .thx BB

 

[Badbob]

+1^^ Also, with a 90* wind it could be that the 31.4-31.8 window node was missed due to a pickup and or let off in the wind (post#25). WD

I see that a 5mph cross breeze can push this bullet out .5" at 100yards. However, the breeze was very consistent and was not gusting. thx bb